Refrigeration apparatus



May 16, 1944. Q BUHLER 2,348,784

REFRIGERATION APPARATUS Filed June 25, 1942 i. I, I Ill [36 i l, 'I I I I; /37 II i| 32 2s 29 d J h r I fi as F: as F: c 5 553:: u

"I" lu l I] EH!- lilgi g n M} II J fill WITNES ES: INVENTOR .CARL But- 2R Q- VN x9 BY ATTO EY Patented May 16, 1944 2,348,784 REFRIGERATION APPARATUS Carl Buhler, Springfield, Mass., asslgnor to Westinghouse Electric Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application June 23, 1942, Serial No. 448,088 6 Claims. (Cl. 62-1) This invention relates to refrigeration apparatus and more particularly to a means for defrosting the cooling unit of such apparatus.

It is an object of the invention to provide novel means for defrosting the cooling unit of refrigerating apparatus.

Another object of the invention is to provide means to selectively defrost portions of the cooling unit.

A further object of the invention is to defrost the cooling unit of refrigerating apparatus without materially raising the temperature of materials in or near the cooling unit.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in accordance with the accompanying drawing, forming a part of this application, in which:

Fig. 1 is an elevation of the upper portion of a domestic refrigerator with the door removed to show the cooling unit and the defrosting device of this invention;

Fig. 2 is an enlarged side elevation of the evaporator and defrosting device of Fig. 1; and,

Fig. 3 is an enlarged sectional view of the defrosting device taken substantially on the line III-11]: of Fig. 2,

Referring to the drawing for a description of the invention, the reference numeral l0 designates the insulated walls of a domestic refrigerator cabinet. An evaporator II is secured to the'lower surface of the upper wall of said cabinet. The evaporator l| comprises two U-shaped sheets of metal "3 and I1 which form a base l2 and two legs l3 and I4.

Depressions are formed in sheet l6 to provide two refrigerant headers i8 and I9. Further depressions are also formed to provide a plurality of parallel refrigerant passages 2|, each of which communicates with both of the headers l3 and i3 and run vertically downward on the legs l3 and i4 and horizontally across the base |2. In the central portion of the base, the passages 2| are joined by a cross passage 22. Horizontal cross passages 23/and 24 are also provided on each of the legs l3 and i4 of the evaporator II, which passages afford cross communication between the passages 2|.

The evaporator II also includes a metal shelf 23 secured in the interior of the U-shaped evaporator II. The shelf 26 is likewise composed of two sheets of metal 21 and 28 in which depressions are formed to provide a refrigerant passage 26. The shelf 26 divides the evaporator into a lower compartment 30 and an upper compartment 34, the latter being used the storage of frozen foods. v

The shelf 26 is supplied through the tube 3| with refrigerant liquid from a compressor-con.- denser unit (not shown). The refrigerant liquid and vapor in the shelf 26 discharges through a tube 32 to one end of the cross passage 22 from where it passes into the passages 2|. The refrigerant liquid vaporizes in the evaporator l| including the shelf 26 and the refrigerant vapor flows into the two headers l8 and is from which it is withdrawn through a suction tube 33 .by the above-mentioned compressor-condenser unit.

-The compressor-condenser unit is controlled by a switch (not shown) responsive to the temperature of the refrigerator cabinet in a manner well known in the art. The normal refrigerant liquid level 46 in the evaporator is above the passages 23 and 24.

The defrosting device of this invention comprises a cylindrical chamber 36 having an axial tube 31 in which an electric heating element 33 is located. The heating element 33 is removable and has a supporting collar 46 secured to it which engages the upper surface of the chamber 36. A conduit 39 connects the upper portion of the chamber 36 with the cross passage 24 and another similar conduit 4| connects the upper portion of the chamber 36 with the cross passage 23. A third conduit 42 connects the lower portion of the chamber 36 with the cross passage 22. The heater 38 is energized through two leads 43, in one of which a controlling switch 44 is located.

Switch 44 is normally open during the operation of the evaporator II, and during such operation, frost will collect on the surfaces of the evaporator When the evaporator II is to be defrosted, the supply of refrigerant liquid through tube 3| is discontinued and the switch 44 closed. This energizes the heater 33 and heats the refrigerant liquid in the chamber 36. The heated liquid in the chamber 36 will flow through tubes 33 and 4| into the cross passages 23 and 24. The warm refrigerant liquid entering the cross passages 23 and 24 flows-downwardly through the passages 2| into the cross passage 22 and from there returns through conduit 42 to the lower portion of the chamber36. Refrigerant vapor formed in the chamber 36 will pass upwardly through the upper portion of the passages 2| and into the headers l3 and I9 and defrost these portions of the evaporator II. This circulation of the refrigerant liquid will continue as long as the heater 33 is energized and will primarily for quickly melt the frost on the walls of the evaporator H. After the frost has melted, switch M is opened and the flow of refrigerant liquid through the tube Si is re-established.

It will be observed that the circulation of warm refrigerant liquid effected by the energization of the heater 38 cannot flow through the passage 29 in the shelf 28, so that the shelf 26 is not defrosted. Frozen comestibles on the shelf 26, therefore, will not be melted during the defrosting operation...

It wil be apparent from the above that this invention provides a novel means for quickly defrosting a cooling unit. It also provides a novel means for selectively defrosting certain portions of a cooling unit containing a refrigerant liquid, so that comestibles in contact with other portions of the cooling unit are not melted.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. In a cooling unit having refrigerant passages therein, a chamber adapted to be heated, at least one duct communicating with said chamber and said passages, said chamber and passages being adapted to contain a refrigerant liquid, said duct and chamber being so located with respect to said passages that when said chamber is heated. warm refrigerant liquid will circulate through said chamber and only a portion of the refrigerant passages of the cooling unit, whereby frost which may have accumulated on said cooling unit, is melted substantially only from the portion of the cooling unit containing the passages through which the warm refrigerant liquid from the chamber is circulated.

2. In a cooling unit providing two refrigerated compartments, refrigerant passages in the walls of each of said compartments, a chamber, said passages and chamber being adapted to contain a refrigerant liquid, means for supplying a refrigerant liquid for said passages and chamber, means for heating said chamber, at least one duct communicating with said chamber and with the refrigerant passages in the walls of one of said compartments in such a manner that when the supply of refrigerant liquid to said cooling unit is stopped and the chamber heated, warm refrigerant liquid will circulate successively through the chamber and through the refrigerant passages in the walls of said one compartment to melt the frost which may have formed thereon.

3. A cooling unit for a refrigerator having an aware;

insulated cabinet, said cooling unit comprising a U-shaped member having refrigerant passages in at least one side and bottom wall, a shelf in said U-shaped member having refrigerant passages therein, means for circulating a refrigerant liquid through all of said passages, a chamber communicating with the passages of the U-shaped member, refrigerant liquid in said chamber, means for heating said chamber, the communication of said chamber with said U-shaped member being such that when said chamber is heated, relatively warm refrigerant liquid from said chamber will circulate through the passages of the U-shaped member and not through the refrigerant passages of said shelf.

4. In a-cooling unit comprising two refrigerant containing portions, a chamber adapted to contain refrigerant liquid, means for suplying a. re-

- frigerant liquid to the said portions and to said chamber, means for heating said chamber, at least one duct communicating with said chamber and with one of said portions in such a manner that when the supply of refrigerant liquid to said cooling unit is stopped and the chamber heated, warm refrigerant liquid will circulate successively through the chamber and through said one portion to melt the front which may have formed thereon, the other of said portions being unaffected by said warm refrigerant liquid.

5. A cooling unit for a refrigerator including an insulated cabinet, said cooling unit comprising a U-shaped member having refrigerant passages in at, least one side and bottom wall, a shelf in said U-shaped member having refrigerant passages therein, means for circulating a refrigerant liquid through all of said passages, a refrigerant conduit connected in parallel with only the refrigerant passages in said U-shaped member, said conduit including a chamber, said chamber being positioned below the refrigerant liquid level in said U-shaped member, and means for heating the refrigerant liquid in said chamber whereby said heated refrigerant liquid will circulate only through said conduit and through the refrigerant passages of said U-shaped member.

6. A cooling unit having a refrigerant passage comprising a first portion and a second portion connected in series, means for conducting a refrigerant liquid through said passage, a conduit in parallel with said second portion of said passage, said conduit including a chamber located below at least the upper portion of the refrigerant liquid in said second portion, said chamber containing refrigerant liquid, and means for heating the refrigerant liquid in said chamber whereby said heated refrigerant liquid circulates through said second portion but not through the first portion of said passage.

CARL BUHLER. 

